Method and apparatus for producing pinking shears



Feb. 16, 1954 K. s. CHRISTENSEN 2,669,133

METHOD AND APPARATUS FOR PRODUCING PINKING SHEARS Filed June 18, 1949 2 Sheets-Sheet 1 Bnventor Jfaj J. (Z7 11? Zensen 20 attorneys 1954 K. s. CHRISTENSEN METHOD AND APPARATUS FOR PRODUCING PINKING SHEARS 2 Sheets-Sheet 2 Filed June 18, 1949 0 5 W L vv/ILVA f '6: m/wza Gttornegs Patented Feb. 16, 1954 PATENT" ossicsi;

METHOD ANnnPr-ARATUsFoa PRODUCI NG. PINKING SHEARS l izti Si Chii stensefi; NorWalk; Conn. Apmicationsuneisiilm,seria1'm;'99,9s3 ioisims; (01.7e 104) Still :another objectt-ofrthe 'inventionrisitoi pro -I,

vide an improved apparatus for. producing a pink?- ing shears characterized as above, which appa-i ratu'sis? simple. i'and inexpensive: to i constrnctzzr-is reliab e? in? iise andhas-' a s-liigh": production? rate; 2 and lowiupkeepn 'A furth'erobj eat ofthe invent bniis tot-provide improvedsheet 'm' etal p k ing' shear blades which are-by them-selves 'v'ery ri'gidp' sturdy-andvdurable; which may be quickly and economically fabrifcated fand the cutting =surfabes 'of whichare perfeet-complements of each' other 'whereb :an' efiEi-a' ci nt andPeiTCtiVG"cutting'iactionxis had; n ling th'dbla'de's to effectively handle all typesfiof' -cut table fabric materia'lsi v Inf'- aecoinpnshing "the aboveobjects tiier provided} inaccordance -with-the{ -inventio 1 pinki g shears' having no'veL- iinproved fblades which" are formed' entirelyof sheet "metal, the t blades" being 50 flangedfshaped' aneerrangee "as method therefore eliminates thefl'sbalg 5 tion being essentially adressingg down lbf t to produce a desirably rigid, rugged and durabledevice which is? extremelybfiec'tiyeinfitsoperatiOIliZ J H In the'jspeci' fie embodiment of ithefinvention illustratedheiiein "this mprovempmk pgs ears coinprises not "only novel, sheet-metalb ables, 40

but'fialsof' novel" assemblages in'clildin metal operating extensions-m handle blades,said-blades and handlesbeing Became seh d entedafi'tl'l "pivot 'of -t 'ef' s hear providing. large, ,fiat -bear g s'u" aces; which? aec'urate'ly control the relative-"positions 0f the blades. Both 1 the blade parts--' {and f-fthe handle parts mayl be quickly andE'eas'ily 'blanked and formed" to 1: the] disclosed shapesand-- readily jassembled to 'each otherj withf a oftnneand equipment being required; this; to-

may be done prior'to the centric v grooves- 'res'ul ts in -the fl ge The sheet metal; blades are' jo rf shearing tapered; "elongate, identical b a Piece of sheet metal, and thenfolding along the, longitudinal" edges of a the b an flanges of each blade extending tjerally the complementary blade whenthese'pa assembled. One. flange of each blajdei'i she throughjinan v lma n r;embracinea ur of different )directions to formlteeth which: have edge surfaces; angularly' dishe nable the t eth: of. ne; ange; to, be.

compl m ntary with. the; teeth Iorth 0th in accurate cutting, -relationsh pMhent e are pivoted to ether and closed .011 his-then; Except. for a lappin o erationJot-limited; xteilt and duration, the shearing through of eachlfla'nge in the isaid. diflerentvdirections, ,towform te constitutes the major final shaping" or'proc of the working edges .of,the, shearlblades millingand ,othernostly forming operations; tofore required. I I

I prefer vto,shear4 through the efiangesbff' he blades. more thanonce thefinalishearing hp:

which have beenspreviously formed r-by, sh and-such dressing down removing but; amount of material. Thewfirst shearing tion to initially form the teeth may be done the flange ,has been bent, up,in, the blah bending of "the flange in, the :longitudinal edge of the bla delwhile ;the latter isa flat,blank.-. V

I The novel shearing ,of thegfian'ga-in ,thgzp ug rality of, different directions bywhich the fin shape orconfiguration is given 1 to, thetteeth accomplished quickly and economically Q0 improved shearing tool provided-by the inve comprising two cooperable elongate die me pivotally connected together to enable- -them-toz swung: n-close'd. hand separa-tedr in, @the manne e of pivoted-shears;said:die membershaving;:eompiee mentar-y teethon opposite;:-worl -ing hedges, ex tended in curves whereby the .surfiaoes of: theiexe-i tensions. :-form curved i- Vegroovese: concentrically disposed aboutr-the pivotal axisof; the-:dieimeme; bers. Means are provided' for releasablys-scon-i-ya necting the -members to'gether forltpivotaltmovee ment; and for positioning nan'gedriblade:fbla nlts between the members with the pivotal centereofii' the blank at th'epivotalaxis of the memsers tne blank being thereby 'h'eld in position-5150" have'fiits t flange shear'ed thrOHghLbyJthe mem'bl'ers'. This: shear ng bycomplementary teeth-{o e I blade being sheared through in a plurality of different directions such that the teeth so formed are properly related to the pivotal point of the blade to enable a perfect cutting relationship to exist with a complementary blade. Both blade blanks, after being flanged and prior to shearing through the flanges thereof to form the teeth, are identical to each other in all respects. A blade blank may be inserted between the die members in one position whereby its flange is sheared through by engagement of one die member with the outside of the flange, and a second blade blank may be placed between the die members in a reversed position whereby its flange is sheared through by the said one die member engaging the inside of the flange. By such arrangement perfectly complemental teeth are formed in the flanges of the two blades, so that when the blades are pivotally secured together the teeth cooperate perfectly and have an accu rate and precise cutting relationship.

The flange on the other edge of each blade reinforces the blade against springing in use and controls the cutting of the teeth in the other flange during the shearing operation as will be more fully explained.

Simplicity and economy, together with durability and effective operation, are thus accomplished by the use of economical sheet metal in forming the blades, by the use of simple shearing tools having few salient working parts, and by the use of simple, rapid processing operations involving shearing of teeth in both blades by the same tools in a manner to enable one set of teeth to be perfectly complemental to the teethofthe other set.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Figure 1 is a plan view of an improved sheetmetal pinking shears made in accordance with the invention.

Fig. 2 is a fragmentary plan view of the tip Fig. 13 is a view like Fig. 11 but showing a modified form of blade blank whereby the shear ing of the teeth in the flange of the blade results in the tooth surfaces being relieved.

Fig. 14 is a view like Fig. 12 but showing a tooth with relieved surfaces, as formed by the process illustrated in Fig. 13; and

Fig. 15 is a fragmentary plan view of a blade blank prior to the flanges being formed thereon, one longitudinal edge of the blank having teeth formed in it by the blanking operation, this figure illustrating a modification of the process of the invention.

Referring to Figs. 1-4 and 12, the improved pinking shears of the invention comprises a pair of complementary blades 20 and 2| formed of sheet metal; said blades are generally flat and are provided on their opposite longitudinal edges with relatively narrow flanges 22 and 23, and relatively wide flanges 22a and 23a, the wide and I narrow flanges meeting at the tips of the blades.

portions of the shears, as they appear when the blades are closed.

Fig. 3 is a fragmentary perspective view of an assembly of a flanged blade blank and attached handle extension, prior to forming the teeth in the flange.

Fig. 4 is a transverse section taken through the pivot of the shears.

Fig. 5 is a top view of a shearing tool for forming the teeth in the flanged blades, one blade assembly being shown in position between the tool members, in readiness for processing.

Fig. 6 is a view like Fig. 5 but showing the complementary blade assembly of the shears, positioned in the tool prior to the processing.

Fig. 7 is a front view of the tool and blade assembly shown in Fig. 6.

Fig. 8 is a section taken on line 8-8 of Fig. 7

Fig. 9 is a fragmentary section taken through the cooperable die members and a blade assembly about to be sheared.

Fig. 10 is a view similar to Fig. 9 but showing a complementary blade assembly between the die members, prior to its being sheared.

Fig. 11 is a fragmentary view similar to Fig. 9 but enlarged and showing a flange partly sheared. through.

Fig. 12 is an enlarged transverse section through a blade, said section being taken on line I[llii of Fig. 1 and illustrating the sheared teeth in the flange, formed in accordance with the steps of. the process indicated in. Figs. 9 and The blades 20 and 2| are provided with eXtension pieces 24 and 25 stamped from sheet metal and having handle portions 2% and 21. The extensions 24 and 25 have relatively large bearlng portions 28 and 29 which engage each other and which are nested in the blades 2!! and 2! and are secured thereto preferably by spot welding as indicated at 30. The assembled blades and handles are apertured and are held together with a required pressure by a pivot bolt 3! carrying a spring washer 32 and nut 33, Fig. 4.

The handle portions 26 and 21 of the shears may be formed integrally with the extensions 24, 25, or if desired be covered by any suitable material such as plastic, formed into jackets 34 and 35.

By an improved and novel process hereinafter described, the wide flanges 22a and 23a of the blades 20 and 2| are provided with complementary teeth 36 and 31, adapted to operate in cutting relation to each other whereby the shears may be used for pinking fabric or other materials.

The blades 20 and 2| are preferably identical to each other except for the formations of the teeth 36 and 3'! in the wide flanges 22a and 23a. As shown in Fig. 12, the distance between the roots of the teeth in the wide flange 22a and the inside surface 38 of the blade is at least as great as, and preferably slightly greater than, the effective width of the narrow flange 22, thereby to enable the crests of the teeth in the wide flanges to clear the narrow flanges when the blades are closed.

Further, the flanges on each edge of the blades strengthen the blades against springing thereof during a cutting operation with the attendant pulling of the fabric rather than cutting it.

I have found that a blade structure made in accordance with the invention, of sheet metal shaped and arranged as set forth above and illustrated in Figs. 1-4 and 12, when formed of a stock of suitable thickness, is extremely durable and rigid, and not only entirely satisfactory but very advantageous when used in shears to pink cloth, fabric and the like; and that blades so formed have highly desirable characteristics, being sturdy, wear resistant, light in weight, and economical to fabricate by tools which have a low upkeep. Moreover, the complementary blades may be made from the same blanks, since they are identical to each other up to the point where the teeth are formed in the wide flanges 22a and 23a. Thus a tool and inventory economy is effected. The flanges of the blades may be made 55 torextenmangula-rly:laterallyaxwitharespechntmathe. blade bodies whereby am attractives alnrtfdesfiiable 1: beveli is provided: alongrthew outer: longitudinal edges, as-indicated atr3 SJ'and ABfimFig: v122; 'When' the blades--12 0. andttl i:are:formedzofiislreet metalf? of suitable thickness, for example approximately of an inch, in the shape and form indicated inethe figures: and swith the narrow and wide flanges along": their opposite" longitudinal edges; theyz-arex rigid and durable, and functioneffectivelyt: totenable; a- .isatiisfactory' cutting: action to beiob'tainedcby "the cooperation of 'the :teeth -36 I and 3.1.?

Thea-blades; and:2 l :are' economical .tofabricate for-several. reasons, one being: that*.the-.op= erationsrinvolved :are. stamping and formingmperations which are simple: and may be carried outzwith' considerable :speedt Another reason: for the; economy; infabricating. the blades is that thessameitoolsmay be used for forming both bladest-zilrand 2 i-wto, their completed shapes, including ithewteeth --36' anri- '31; therefore tooling costs :arereduced. The handle extensions. 24 and zfufor the bladesare-alsoeconomical total).- ricate; since :they. may, be "formed of inexpensive. sheet'metal-andrblanked to the desired shape; and-may vbesecuredto. the-blades by a quickI and economical spot welding operation. The. method of forming the teeth 36 and -31 in vthenblades 20 andzz2 t, isieconomica-l and at. the same time providesmerieotly; -formed teeth which are perfectly complementary to 2 each: other: throughout the lifeaofthe dies whereby,a-fter a simple and short lapping, finishing operation a .very srnoothaction: issobtainedvwhen: operating: the shears. Thus I have 2 provided: by) this 1 invention: an a improved pinking shears which is sturdy and durable; light in:;weight,-- effective: in: use and extremely 'eco-- nomicalto fabricate; and which is; convenient in use-:andis et-attractive: and; finished: appearance:

. The-bearing surfaces;- 28nands: 29 .provided bythezblade extensionszze an-d1:25"ar.e perfeotly fiat, ands provide a;: stable. assemblagewhereby the spacing: between:- thelablades 1 is' accurately" controlled; and; holds during." the: operation"; of the; shearsnvithout theruse .ofrth'e; usual shims which; requirenmuch: time -rand efiort= to properly :assems I ble and adjust.

through the r-zwide; flanges 2 2 a aand 2 3a z of I the- 50.;

blades-1 in: a: plurality: of diiiierent directionsa wherebyperfectly:complementaryzteethr are proe vided' 01111711618835 -:of .blades'; the';.surfaces.; the teeth being properly-related: to;;th'e pivot" of-r' theeblades to;enableoanzcaecuratetzcutting elaw;v 5

tionship; to :exist, :an.d::to :ena'blezunimpededi relae time: pivotal: movementzof; the bladesrto oocun As; shown :in Figs: 5 and .6; the improvedsshear- I ing ---toolor. this :inventionwoomprises aslpairxior; cooperablerelongate "die: members .4 hand 42.:concnectedetogethenzby pivotstudsassembly 43, Fig;

8; whereby :the=;memhers maybeswung-:closed or:- separated:in. the manner. of. pivoted shear blades-v- The die member 4| has atpluralityrofmurved. V

gmoizesfll pnovidedrin.sitsiinnentacei liathessaid 78% ges- $1 1511 grooressbemgecomentrie with:eachrotherrxand having a common center at the pivot stud'assembly 43 The iace llii ofsthei' die: member 4 l-s is alsoerel-iieved-sor reoessedizati ifi; Figs? 6L'an'di9,'toprovide a2 nestrfomrtheeblade 520i of 1 the shears, the-saidfibladerandrhaiadletextension .Zdwbeingrinsortable betweemtheadie members positionable by thetpivot stud assemblyafl of.lithe-etco1"? Thendie; member; 42 has; a:-:.plurality. of icurved vegroovesl fl in: its inn-erzfaceesaid'sgrooves :being alsoaconcentricrmth ires-p'ect'ito: :each other and havinguamcenter in :the ipivot stud? assembly. 435 Theizgroovesi 411* are :staggeredziwith relationi'to" theegrooyesrflzso asztoabe perfectly complementahtheretoa: 'Tlre' zdi'eimember 42 :has. a :relief or whiclr thenbladeuz'l iof theshears 'maybe nestedwhen theeblade is' i interposed.r'between -.the:. die

members. as. showmin-zFigza 5: It Will be under.

;.-stoodrthat?theredgesfl'50fthe nest 46 in the die members constitutes a leadingzor cutting edge ofiathierdie membemandxthe same is truea of the edgezfi 0* tin thezdiermember; 42;

Thetdiermemb'ers' .-'.4 i-zandsi! .ztare pivotallycon-.- i; neeted togethen' byfa'the sti'idii-assembly :43 in such azmann'er athat itheemembers maywb'ereadily-sepa rated from each other to enable a bladezito be.

intenposedebetween: them-s To accomplish 1' this, thesstudaassemblyxflt lis 'formedcot a shank 51 se-.

21 curedrtottheldie' memben'a iziby a'zsetscrew 52 and composed-i 0121; a; cooper-able rshank 53 1: secured. to

jection:=:56 son thewshank 553; :and :th'eiextension' 5t is: of-zazadiameterzto enableiit :to. 'closelyfit' the aperturesinrthe'1bladeassemblies in the shears.-

As r showmin-Figs; 6 5117-. andz B gsthe .ablade '2 0 and extBIlSiOIIZf'Z I tEBI'GOf imay' be positioned between thersh'anks 5 I fan'zl 5 3) with the shank projection 5fi passing through the-aperture in the blade assembly; and th'e blade 'zfl maybenested in the rethe shearirig -edge fl thereof-Will engage-the in I side of the flange 22a of the blade, and-Will'she'ar throughithe fiange progressively; starting at the tipnofi'fthe' bladeoithereby .cp'rogressively' forming 'teeth' in =theeflanger Different portions of the flange will beshearedthroughin different 'directions bywthedie members 4i and -M, and the resulting-. surfaceskof thecteeth formed by the shearingwill have asd e'finite' predetermined re- -'lationship to the pivotal axis oi'the die member and-ofthei -blade 20, such relationship being that required td enable the teeth .to" perfectly corn-- plement sthe t'eeth ofthe complementary blade I 21:;

will-eti'lt as shown in Fig." 13:?and cutthrough as provider a srelievedr cutting properlywselecting' the heightsofzs shot/min Ei I The shearing-action set forth above is' clearly As will -be 'noted from "Fig. 9; l the the flange 22 the shape of the tooth can be controlled.

In accordance with this invention the die members 4| and 42 are also utilized to shear through the flange 23a of the cooperable blade 2| of the pinking shears, and to form the teeth 31, which teeth are perfectly complemental to the teeth 36 formed in the blade 20. To accomplish this, the blade 20 is removed from between the die members and the blade 2| placed between the members but in a reversed position to that occupied by the blade 20 with flange 23 resting on crests of the teeth on die 4|. This is clearly shown in Figs. 5 and 10. The blade 2| occupies the recess 48 in the die member 42. The pivots 5|, 53 will be adjusted so that blade 2| is pressed against the bottom of the recess by engagement of the end of pivot 53. While the pivots are disclosed herein for purpose of illustration as being held in adjusted position by set screws 52, 54, it should be understood that they may be held by other suitable means as required. When two die members are brought together, continued movement of the die member 42 will cause the flange 23a of the blade 2| to be sheared through whereby the teeth 31 will be formed thereon.

It will be noted that the leading or cutting edge 5|! of the die member 42 engages the inside of the flange 22a of the blade 20, whereas it engages the outside of the flange 23a of the blade 2|. By this arrangement the teeth 3! formed in the blade 2| are made to be the exact complements of the teeth 38 formed in the blade 20.

It is preferred to cut the blades for each pair of shears in succession. This insures that the teeth of each pair will be identical even though the dies may be worn. When the cutting edges of the dies become dulled, it is merely necessary to take a light out off of the flange-engaging of the recesses to provide a new cutting edge thereon. Thus it will be seen that normal wear in the dies will not alter the complemental relation between the teeth of both bladesand that the cutting edges of the dies can be renewed easily to provide a long die life for accurate and satisfactory use.

Aiter the shearing of the flanges of the blades to form the teeth 36 and 31 therein, the teeth may be given a light lapping or polishing to provide a final fit by assembling the blades 2|] and 2! to each other and employing the usual lapping procedure. At present I prefer, prior to such lapping, to dress down the teeth 36 and 3! by placing the blades in a second tool similar to the tool comprising the die members 4| and 42, the second tool removing a very small amount of stock from the teeth previously formed. I have found that as little as .005 inch of stock may be removed in the second shearing operation, to accurately dress down the teeth.

The die members 4| and 42 may obviously be actuated in any suitable manner, and may be provided with threaded holes 58 by which actuating means may be connected to them.

If desired, as shown in Fig. 15, the blade 29 of the shears may be blanked out and the teeth 36 formed therein simultaneously with said blanking while the blade is in the flat state. If this is done, the subsequent forming operation for bending up the flanges 22 and 22a will bring the teeth approximately to the positions shown in Fig. 1, and a subsequent dressing down operation may be employed by the die members 4| and 42 to give 8. the teeth 36 their final finished configuration except for the lapping or finishing operation.

Variations and modifications may be made made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. The method of forming teeth in a set of cooperable, longitudinally flanged, pinking-shear blades each having a leading and trailing edge which includes the steps of shearing through a longitudinal flange on the leading edge of one blade by a pair of cooperable tooth-forming die members one of which engages the inside of the flange while at the same time positioning the trailing edge of the blade by said one die member, and thereafter shearing through a flange on the leading edge of the other blade by the same cooperable die members the said one of which engages the outside of the flange of said other blade, while at the same time positioning the trailing edge of the blade by the other die member, the engagement between the trailing edges of the blades and the die members controlling the relief of the surfaces of the teeth, thereby to cause the toothed flanges to be complementary and engageable with each other in cutting relationship when the blades are pivotally connected and closed on each other.

2. The method of making pinking shears consisting of a pair of pivoted blades having flanged cutting edges which comprises the steps of placing one blade face upward between a pair of pivoted dies movable about the pivot point of the blade and having complemental surfaces defining the pinlring teeth; moving the dies relative to one another about the pivot to shear teeth in the flange, each tooth having a cutting surface concentric with the pivot; removing the blade and inserting the other blade, facedownward, between the dies; moving the dies relative to one another about the pivot therefor and for the blade to shear teeth in the flange which are complemental to the teeth in the flange of the other blade, removing the second blade from the dies, and pivotally connecting the blades face to face with the teeth in the flanges in cooperative cutting relation.

3. A tool for shearing through the flanges of flanged pinking-shear blades to form perfectly complementary teeth therein, comprising a pair of cooperable, elongate die members having rows of complementary teeth on opposed working edges, the edge surfaces of the teeth of each member being in predetermined relationship to a center which is located on the member, and out of line radially with the row of teeth thereof, and beyond the end of said row; and means releasably connecting the members together for pivotal movement about the said centers and for positioning a flanged blade blank between the members so that the pivotal center of the blank coincides with the pivotal axis of the members whereby the flange of the blank is held in position to be sheared through by said members, each of said die members having a nest to enable the blade blanks to be reversibly positioned between the members and to lie in one or the other of said nests so that the inside of a flange being sheared through may be engaged by one or the other of the die members according to the position of the blank and said die members having trailing surfaces for engagement with the trailing edges of the blanks.

4. A tool for shearing through the flange of 9 a flanged pinking-shear blade to form teeth therein, comprising a pair of cooperable, elongate die members having rows of complementary teeth on opposed working edges, the edge surfaces of the teeth of each member being in predetermined relationship to a center which is located on the member, and out of line radially with.

the row of teeth thereof, and beyond the end of said row; and means releasably connecting the members together for pivotal movement about the said centers and for positioning a flanged blade blank between the members so that the pivotal center of the blank coincides with the pivotal axis of the members whereby the flange of the blank is held in position to be sheared through by said members, one of said die members having a nest for receiving the blank, and--v the other die member having trailing surfaces for engagement with the trailing edge of a nested blank to control the canting of the blank during the shearing of the flange thereof whereby the relief of the sheared surfaces is controlled.

KAJ S. CHRISTENSEN.

References Cited in the file or this patent UNITED STATES PATENTS Number Number Name Date Jansson Jan. 18, 1921 Alleman Aug. 21, 1923 Dahl Mar. 28, 1933 Kelley May 8, 1934 Wyner et al May 15, 1934 Weidauer Aug. 14, 1934 Kissling June 2, 1942 Schwartz June 16, 1942v Weidauer July 4, 1944 Brown Oct. 16, 1945 Elm, Jr Aug. 28, 1951 Sorensen Dec. 25, 1951 FOREIGN PATENTS Country Date Great Britain Jan. 22, 1878 Great Britain Feb. 28, 1936 France July 24, 1933 

